There’s a saying in the recovery movement: Alcohol and drug addiction can cause mental illness but mental illness does not cause addiction. However, some mental illnesses, especially those that are not quickly diagnosed and treated, can trigger the use of alcohol and drugs.

Depressive disorders often cause acutely uncomfortable feelings such as overwhelming sadness, hopelessness, numbness, isolation, sleep disorders, digestive and food-related disorders. It is tempting, if medications aren’t being prescribed or used properly, for people suffering from depression to self-medicate.

This can compound the depression and make it far worse. A drink or two, a line of cocaine or two, might temporarily relieve some symptoms, but the backlash when the chemical leaves the body brings the depression to new lows. This “withdrawal depression” happens each time an abused chemical leaves the body, though many people don’t experience severe symptoms at first. The withdrawal depression itself can trigger the use of more alcohol or drugs because they will help get rid of the bad feelings.

Another compounding problem is that if drugs and alcohol are being used while medication is being taken, the alcohol or drugs can actually potentiate—make stronger—or deactivate the medication. Either way, this can put the person in medical danger.

Because of their personal life-shattering experiences with substance abuse, some people in recovery are leery of using any drugs, even prescribed ones. They have faced traumatic experiences with addiction and have a difficult time coming to terms with the necessity for medication intervention. In fact, I have had patients who have quit drinking or drugging the hard way—through willpower or cold turkey—yet are willing to endure the horrible symptoms of depression rather than take medication. Very often their social sober support network advises them to refrain from taking meds. Usually, this is not within the realm of the advisor’s authority. Dually-diagnosed patients (those with both mental illness and addiction) should speak with their psychiatrist about this issue, not a friend, no matter how well-intentioned.

One question I get asked frequently from addiction-treatment patients who are diagnosed with depression after they are diagnosed with an addiction is “did my drinking or drugging cause the depression?” The initial answer is always a resounding “maybe.” A well-trained psychotherapist will often be able to tease out the source of the depression and find out if it existed before the patient came in for addiction treatment. Therapists use a psychosocial evaluation and reports from family, friends, employers, court and police records and the like to help determine which condition occurred first.

Why is it important to know when the depression first occurred? Because someone who had depression before they began to abuse substances will most likely need treatment, including medication intervention, for a longer period of time compared to someone whose depression was caused by the cycle of addiction. Someone whose depression was caused by substance abuse generally will not need the same treatment as someone whose depression preceded his or her substance abuse.

Sometimes when someone comes in for addiction treatment and has a depressive disorder that was caused by addiction, they aren’t able to accurately report what is going on for them. They may be too numb or sad or unable to focus. Or perhaps a less-than-thorough psychosocial evaluation is done. Lack of reporting or inadequate evaluation may prevent the full understanding of whether the depressive disorder preceded or was caused by the substance abuse.

If a patient whose depression was caused by chemical abuse is referred to a treatment track for those who were depressed first and chemically dependent later, within a few weeks he or she usually is asking “what am I doing here? I don’t have these kinds of problems!” In these cases this isn’t necessarily a function of denial but a valid observation due to an original lack of understanding about whether the depression or the addiction came first.